/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.catalina.tribes.group.interceptors;

import org.apache.catalina.tribes.ChannelException;
import org.apache.catalina.tribes.ChannelMessage;
import org.apache.catalina.tribes.Member;
import org.apache.catalina.tribes.group.ChannelInterceptorBase;
import org.apache.catalina.tribes.group.InterceptorPayload;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

/**
 * @author Filip Hanik
 * @version 1.0
 */
public class GzipInterceptor extends ChannelInterceptorBase {

	public static final int DEFAULT_BUFFER_SIZE = 2048;
	private static final Log log = LogFactory.getLog(GzipInterceptor.class);

	public static byte[] compress(byte[] data) throws IOException {
		ByteArrayOutputStream bout = new ByteArrayOutputStream();
		GZIPOutputStream gout = new GZIPOutputStream(bout);
		gout.write(data);
		gout.flush();
		gout.close();
		return bout.toByteArray();
	}

	/**
	 * @param data Data to decompress
	 * @return Decompressed data
	 * @throws IOException
	 */
	public static byte[] decompress(byte[] data) throws IOException {
		ByteArrayOutputStream bout =
				new ByteArrayOutputStream(DEFAULT_BUFFER_SIZE);
		ByteArrayInputStream bin = new ByteArrayInputStream(data);
		GZIPInputStream gin = new GZIPInputStream(bin);
		byte[] tmp = new byte[DEFAULT_BUFFER_SIZE];
		int length = gin.read(tmp);
		while (length > -1) {
			bout.write(tmp, 0, length);
			length = gin.read(tmp);
		}
		return bout.toByteArray();
	}

	@Override
	public void sendMessage(Member[] destination, ChannelMessage msg, InterceptorPayload payload) throws ChannelException {
		try {
			byte[] data = compress(msg.getMessage().getBytes());
			msg.getMessage().trim(msg.getMessage().getLength());
			msg.getMessage().append(data, 0, data.length);
			getNext().sendMessage(destination, msg, payload);
		} catch (IOException x) {
			log.error("Unable to compress byte contents");
			throw new ChannelException(x);
		}
	}

	@Override
	public void messageReceived(ChannelMessage msg) {
		try {
			byte[] data = decompress(msg.getMessage().getBytes());
			msg.getMessage().trim(msg.getMessage().getLength());
			msg.getMessage().append(data, 0, data.length);
			getPrevious().messageReceived(msg);
		} catch (IOException x) {
			log.error("Unable to decompress byte contents", x);
		}
	}
}
